1. Technical Field
The present invention relates, in general, to a spindle motor.
2. Description of the Related Art
In general, a spindle motor can maintain high precision rotation characteristics since a bearing having a rotary shaft therein rotatably supports the rotary shaft. Thanks to this characteristic, the spindle motor is widely used as a driving means of a hard disc drive, an optical disc drive, and other recording media, which are required to rotate at a high speed.
This spindle motor generally uses a fluid dynamic bearing, which feeds a certain amount of oil between the rotary shaft and a bearing that supports the rotary shaft, in order to facilitate the rotation of the rotary shaft, and causes dynamic pressure to be generated when the rotary shaft rotates.
In particular, entering the 2000s, the shaft system of the spindle motor has experienced an abrupt change whereby a dynamic bearing has been used to substitute for a ball bearing. The dynamic bearing has advantages in that it has little noise, better shock resistance, and a longer lifetime compared to the existing ball bearing.
However, due to the trend of the spindle motor for a Hard Disc Drive (HDD) towards a small size and a thin profile, there are many problems in that it becomes difficult to provide the length of the shaft system and thus the reliability of the product decreases.